Concrete pipes are a tough option for the tough times

When the going gets tough, the tough get going, goes the expression. Andy Goring argues that with the times being tough - what with the recession and new policies for flood mitigation - concrete pipes could be an appropriately tough response.

This year promises to be one of the most challenging times for the sewerage and drainage sector.

There is the current economic downturn affecting the construction industry, and new policies being developed to deal with flood mitigation and drainage works. There is also the additional PR09 requirements addressing different sustainability issues for sewerage systems, drainage networks and construction operations. It is evident that 2009 will be an extraordinary year for the sector.

Robust solutions

The concrete pipeline industry has been working on a range of economic, durable, and robust solutions over the past few years to add new strengths to this product. These solutions address the concerns of the industry. All the Concrete Pipeline Systems Association’s (CPSA) products and systems share a number of characteristics that will prove vital for 2009 and beyond. These characteristics are demonstrated in a CPSA’s publication due out in the first quarter of this year.

This year will be a recession year for the UK. With the downturn, costs and expenses will be an increasingly major driving force in infrastructure projects. But using concrete pipeline products can offer the contractor a major cost advantage. In addition to the relatively low cost of sourcing and producing concrete drainage products – compared with other viable alternatives in the market – the cost of bedding can be significantly reduced as concrete pipes can be laid using lower grade bedding Classes B, F and even N (for up to two metres).

Reduction in bedding means less virgin aggregate is sourced. Given the current price of aggregates and transport expenses for delivery and removal of spoil, this can make considerable savings on every metre of pipeline laid. Installation costs can also be reduced as the available heavy machinery on sites can be easily employed in the handling and installation of pipes and manholes. Of increasing importance to contractors – who are responsible for more and more future maintenance – is the very low probability of early product failure and low maintenance requirements.

The concrete drainage sector is working to communicate more with contractors to help them become more cost efficient, and take advantage of all these aspects.

There are other challenging problems that might start to surface again as soon as the current credit problem is eased. These may start affecting the industry even before the downturn is completely over. They include problems with raw material availability and surges in crude oil price.

Despite the current low oil prices there is still a high level of uncertainty about the stability of these prices as OPEC looks to cut back production.

This did not reflect on prices in the last quarter of 2008 because of huge hedge fund investments in oil, and the 10% reduction in global oil consumption experienced lately. No pipeline manufacturing sector is completely immune from such scenario, but the concrete pipeline sector should be in a better position as concrete products are less susceptible to surges in oil price.

Pipe material qualities, such as inherent strength and resistance to damage, will continue to be a main selection criterion for contractors in 2009. With all ranges of concrete pipeline products designed to Strength Class 120 (BS 5911: 2004), concrete pipes and manholes now offer the most inherently strong option in the market. Unlike other vulnerable pipe alternatives where the structure of the system will need to be built around the pipeline, the structural robustness of concrete pipes makes it less susceptible to the effects of poor bedding and installation. A good example demonstrating the strength of concrete drainage systems was made by Norwegian concrete pipe organisation BASAL two years ago. But contractors are not only looking for inherent strength, they will also be looking for other advantages that can be associated with this strength. With concrete pipes this could mean a number of things – it means the product can be less affected by damage caused by jetting or by different solid objects being drained into the system during floods and normal surface drainage. Using concrete pipeline products it means the system can be modified and customised as holes can be drilled and portions of a pipe wall can be removed without impact on structural integrity.

It should also be noted that concrete pipeline systems will gain more strength over time as the concrete continues to absorb CO2 for many years. This clearly makes it more durable than other systems on the market. Most industry standards in the UK and abroad specify a default 100-plus years of service life to different concrete drainage products.

Other advantages that developers might prefer in a concrete pipeline product include resistance to jetting pressure (exceeding 5,000psi), resistance to degradation from heat or normal UV light, and improved abrasion resistance. With advances in concrete mix designs, concrete drainage products today have considerable resistance to thaumasite sulphate attack.

Research project

This was proven in a recent Partners in Innovation research project conducted by BRE. All these benefits should continue to influence contractors’ material selection decisions in 2009.

Following the Pitt Review and Future Water recommendations in 2008, flood mitigation will continue to be a major topic for the entire sector in 2009. There are a number of outstanding questions that concrete drainage systems can help answer effectively.

Floods in 2007 exposed the vulnerability of many urban developments in the UK to the dangers of flash flooding. One of the case studies was that of the flooding that occurred at Thatcham, where the dangers of overland flow were evident. There is no doubt that SUDS will offer our best option to minimise the pressure on existing drainage systems, but other solutions should be employed on a wide scale to combat flooding, especially in areas where SUDS usually fail.

There are a wide variety of products and systems available for contractors and developers to enhance surface drainage and mitigate the impacts of floods in densely populated urban areas, areas with heavy clay soil and other locations where SUDS usually fail to eliminate the problem. Highly customised solutions, comprising networks of pipelines with attenuation and storage tanks and employing a wide range of concrete products – such as soakaways, elliptical pipes, attenuation and storage tanks, box culverts – can be employed successfully in clearing huge volumes of rainwater in shorter periods of time. These systems proved to be a major success in countries such as the Netherlands and can be used here to complement SUDS solutions.

Water companies also have the option of enlarging the capacity of underground drainage systems in areas where overland flow and SUDS can pose a danger to public. This is a measure that CPSA has called for following the 2007 summer floods and it can be fulfilled using large-scale concrete pipeline systems (with diameters reaching well over 2,400mm).

Climate change

According to the PR09 review, 2009 also promises to be the year of sustainability for the water and wastewater industry, with issues such as recyclability and climate change becoming central to water company policies and procurement efforts. Sustainability is another advantage for the concrete pipe industry.

Throughout the years the concrete drainage industry has managed to reduce the carbon footprint of its products considerably. In addition to the advantages associated with a locally based supply chain and shorter distances travelled in sourcing and manufacturing the products, manufacturers now use fly ash to partially replace cement. This can reduce the carbon footprint of the product by up to 20%.

Less bedding is also used, which helps manufacturers reduce their impacts by nearly 10kg of CO2 equivalent per tonne of aggregates saved. This is as well as significant reductions in cost and emissions associated with disposing of spoil.

With Site Waste Management Plans becoming compulsory, construction waste reduction and recyclability must gain more importance in 2009. Concrete pipeline products should offer a major advantage for contractors. This is because minimum waste is generated on site, and concrete waste can be crushed and recycled on site for reuse in many applications.

It is also important to alert contractors to the other sustainability advantages of concrete pipeline products. Concrete drainage products are set to be among the first generation of construction products to be declared as responsibly sourced in 2009, meaning an approved system of robust social, ethical, environmental, and quality measures is in place throughout the product’s chain of custody. With the release of BRE’s responsible sourcing standard (BES 6001), the concept of responsible sourcing will gain more importance.

There is no doubt that 2009 will be a difficult year for the construction industry. The concrete drainage industry can help contractors meet the new challenges they face.

The CPSA’s products have evolved considerably and can today offer a much stronger, more sustainable, more durable, and a more cost effective option.

Andy Goring is chairman of the Concrete Pipeline Systems Association

T: 0116 253 6161

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